Rocker arm oiling system



g- 11, 1964 P. F. BERGMANN ROCKER ARM OILING SYSTEM Filed Feb. 14, 1962 INVENTOR.

5401 F fiffW/V/V ,4 Tram/E V5 United States Patent 3,144,094 uocuau ARM OILING SYSTEM Paul F. Bergmann, North Muskegon, Mich, assignor to This invention relates to valve lifting mechanism for internal combustion engines, and more particularly to a valve lifting mechanism having a controlled lubrication flow system through the hollow push rod for the rocker arm assembly.

In a conventional system of lubricating the rocker arms of an overhead valve internal combustion engine, an oil passage is provided in the engine block, from one of the main oil galleries to the top face of the block, then through the cylinder head casting to the top thereof, then to one of the rocker arm shaft brackets, and then to the inside of the hollow rocker arm shaft, from which oil is fed through small ports to each rocker arm for lubrication of the wearing surfaces in the upper part of the valve train. This is a relatively expensive system, and my invention, of providing oil to each rocker arm from its own push rod and tappet, is simple, effective and inexpensive.

Flow regulation is required for rocker arm lubrication. Too much lubricant supplied to the rocker arm assemblies through the hollow push rods creates difficulties such as lubricant draining into the cylinders and excessive pressure loss in the main oil gallery. Attempts to regulate the lubricant flow by the use of tiny restricted orifices or passageways have been unsuccessful since the passageways must necessarily be only a few thousandths of an inch in diameter and as a consequence, are prone to plugging by small particles of foreign matter such as dirt. Once plugging occurs, flow of lubricant is completely stopped and the entire rocker arm assembly lacks proper lubrication. Thus, restricted orifices have not been reliable heretofore even though relatively inexpensive to provide.

It is an object of this invention to provide a valve lifting mechanism having a unique restricted flow system for regulating lubricant flow to the hollow push rod for the rocker arm assembly that does not plug. The flow system inherently provides a self-washing feature to constantly clean the regulating means. The regulation means is inexpensive to manufacture merely by slightly varying the ordinary machining operations performed on conventional, one-piece, valve lifting elements. No extra components are needed. No added valving elements are utilized and yet the regulation means simulates a valving action using the inter-cooperation of the engine valve lifting components.

These and other objects of this invention will be apparent upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a sectional fragmentary cutaway View of an internal combustion engine showing the novel valve lifting assembly with flow regulation means;

FIG. 2 is an enlarged fragmentary sectional view of the interfitting tappet and push rod illustrated in FIG. 1;

FIG. 3 is an enlarged fragmentary view of a tappet and hollow push rod of a valve lifting assembly with a slightly modified interfit therebetween from that illustrated in FIG. 1;

FIG. 4 is an enlarged sectional view of a push rod 3,144,094 Patented Aug. 11., 1964 and tappet modified to provide a slightly different regulation effect; and

FIG. 5 is a fragmentary sectional enlarged view of a. further modified tappet and push rod to obtain still a different flow effect.

Basically, the invention comprises, in a valve lifting assembly, a tappet adapted to ride on a cam surface and including a push rod seat, a hollow push rod having an end adapted to interfit with the push rod seat, a lubricant entrance port in the end of the rod, a lubricant passageway in the tappet communicating with a reservoir and emerging in the push rod seat, and the outlet port of the passageway being spaced from the push rod entrance port to prevent direct flow of lubricant therebetween. Thus, the lubricant is restricted in its flow since it must pass between the convex push rod end and the concave seat in a restricted manner. When the seat and end are forced together upon opening of the engine valve by the valve train, lubricant flow is diminished substantially or completely. When the elements separate due to slack in the valve train with closing of the engine valve, the flow increases substantially through the resulting clearance to lubricate the rocker arm assembly.

In one form of the invention, a shallow recess is provided in the push rod seat between the two spaced ports to enable a small flow to occur even when the valve train slack is removed upon opening of the engine valve. In another form of the invention, the outlet port partially registers with the side of the push rod to enable exhaust of some lubricant along the side of the push rod to reduce the oil flow to the rocker arms to the desired amount.

Referring now to the drawings, in the form of the invention illustrated in FIG. 1, internal combustion engine 10 includes an engine block 12 having an oil gallery 14 therein which comprises a reservoir supplied with lubricant by a conventional engine oil pump (not shown). The engine includes a conventional cam shaft 16 having a plurality of cams, two of which are here shown as 18 and 20. Tappets 22 and 24 reciprocate in their respective tappet bores 28 and 30 with the action of the cams.

Each tappet includes an annular groove in its periphery communicating with the oil gallery 14. In the upper end of the tappets are concave push rod seats 34 and 36 respectively, into which the lower convex ends of the hollow push rods 38 and 40 fit. The upper ends of the push rods operate conventional rocker arm assemblies (not shown) which in turn open and close the engine valves (not shown). In the lower convex ends of the hollow push rods are lubricant inlet entrance ports 44 and 46.

In the tappets 22 and 24, passageways 48 and 50 respectively extend between the annular groove around the tappet, thus communicating with the oil gallery or lubri cant reservoir, and the respective push rod seat. Each oulet port at the seat of each passageway of the tappets is offset from the entrance port in the push rod. This prevents direct flow therebetween. Rather, flow between the outlet port of the passageway and the entrance port in the push rod must pass a short distance through any clearance between the convex push rod end and the concave push rod seat.

In the form of the invention illustrated in FIG. 1, therefore, when tappet 22 is raised on the lobe or nose of cam 18 (which occurs when an engine valve is opened), push rod 38 is forced tightly against the push rod seat 34 by the bias of the valve spring (not shown). This prevents oil flow between passageway 43 and entrance port 44. As the cam shaft 16 rotates further, tappet 22 will be lowered, for example like tappet 24 is lowered onto the base circle of cam 20 to allow the engine valve to close. Since on operating valve train clearance of approximately ten thousandths of an inch then exists, the convex end of the push rod is forced by the lubricant pressure away from the push rod seat to create a somewhat restricted and regulated flow between passageway 50 and entrance port 46. During this brief time interval, enough lubricant flows from gallery 14 through passageway 50, between the concave push rod seat and the convex push rod end, through entrance port 46, and up through the hollow push rod to the rocker arm assembly. As soon as the cam shaft rotates sufliciently to again raise the tappet on the nose of the cam, the push rod is again forced against the push rod seat to stop the flow. Even if a particle of dirt should tend to catch between the push rod seat and push rod end, the liberal pulsing flow as the components move apart wash it out in a self cleaning, valving action.

It may be desired to provide a more coextensive interfitting between the push rod seat and the push rod end than that shown in FIG. 1. Thus, in FIG. 3 push rod end 100 and push rod seat 102 provide an even more effective flow seal between lubricant in passageway 148 of tappet 122 to inlet port 144 in push rod 138-.

In some engines, it may be desirable to provide a small flow through the system even when the valve train slack is taken up. Thus a shallow recess 202 can be formed in the face of the push rod seat (FIG. 4). When the convex end of push rod 238 is pressed tightly against the push rod seat, a small restricted flow still occurs between the passageway 248 of tappet 222 and entrance port 244 of hollow push rod 238.

Still further, it may be desired to provide an interfit such as that between push rod 338 (FIG. 5) and push rod seat 302 with the lubricant passageway 348 located in partial or limited communication with the side of the ush rod. This allows some exhaust flow of pressurized lubricant around the end of the push rod and along the side to lessen the amount of flow between the outlet port of passageway 348 and entrance port 344 of push rod 338.

Various other modifications will occur to those in the art upon studying the foregoing principles and forms of the invention illustrated, without departing from the invention taught. Such modifications are deemed to be part of this invention, which is to be limited only by the scope of the appended claims and the reasonably equivalent structures thereto, rather than the specific forms serving to illustrate the invention.

I claim:

1. In a valve operating mechanism of an internal combustion engine, the combination of the following components: a tappet adapted to ride on a cam surface and including a push rod seat on one end thereof; a hollow push rod having one end interfitting with said push rod seat and in at least one position of said tappet providing a clearance between said push rod seat and said one end of said push rod; said push rod having a lubricant entrance port in said one end; said tappet having a lubricant passageway communicating with a lubricant gallery; each of said tappet and push rod components having a central axis, and at least one of said push rod port and tappet passageway being off the central axis of its respective component, with said passageway communicating with said push rod seat at a position offset from said lubricant entrance port whereby lubricant flowing from said passageway to said port must flow through said clearance between said push rod seat and said push rod end to thereby regulate the flow to said hollow push rod.

2. In a valve operating mechanism of an internal combustion engine, the combination of the following components: a tappet adapted to ride on a cam surface and including a push rod seat on one end thereof; a hollow push rod having one end interfitting with said push rod seat, and in at least one position of said tappet providing a clearance between said push rod seat and said one end of said push rod; said push rod having a lubricant entrance port in said one end; said tappet having a lubricant passageway communicating with a gallery; said one end and said seat comprising mating curved surfaces; each of said tappet and push rod components having a central axis, and at least one of said push rod port and tappet passageway being olf the central axis of its respective component, with said passageway communicating with said push rod seat at a position offset from said lubricant entrance port to necessitate lubricant flowing to said entrance port to flow through said clearance between said seat and rod end; said surface being in abutting relationship when said assembly operates to open a valve, to thereby throttle the flow from said passageway to said port, and said surface being slightly spaced upon closing of said valve to permit liberal flow therebetween from said passageway to said port.

3. In a valve operating mechanism of an internal combustion engine, the combination of: a mechanical valve lifting tappet adapted to ride on a cam surface and including a concave push rod seat on one end thereof; said tappet having an annular groove adapted to register with an oil gallery in the tappet bore of an internal combustion engine; a hollow push rod having a convex end interfitting with said push rod seat and in at least one position of said tappet providing a clearance between said push rod seat and said one end of said push rod; said push rod having a lubricant entrance port in said convex end; said tappet having a lubricant passageway extending between said groove and said push rod seat; said passageway emerging from said tappet at said push rod seat to form an outlet port; said tappet having a central axis and the outlet of said tappet passageway being spaced from said central axis so that said'outlet port is offset from said entrance port such that lubricant flowing through said passageway and said outlet port must flow between said push rod end and said push rod seat before flowing through said entrance port.

4. In a valve operating mechanism of an internal combustion engine, the combination of: a tappet adapted to ride on a cam surface and including a push rod seat on one end thereof; a hollow push rod having one end interfitting with said push rod seat and in at least one position of said tappet providing a clearance between said push rod seat and said one end of said push rod; said push rod having a lubricant entrance port in said one end; said tappet having a lubricant passageway communicating with a gallery; said passageway emerging from said tappet at said push rod seat to form an outlet port; each of said tappet and push rod components having a central axis, and at least one of said push rod entrance port and tappet outlet port being off the central axis of its respective component so that said outlet port is offset from said entrance port and non-coincidental thereto to throttle off and prevent direct flow therebetween; and said push rod seat having said clearance from said push rod end when said tappet is in said one position to allow lubricant flow therebetween when said end lifts off said seat.

5. In a valve operating mechanism of an internal combustion engine, the combination of: a tappet adapted to ride on a cam surface and including a generally concave push rod seat on one end thereof; a hollow push rod having a convex end interfltting with said push rod seat and in at least one position of said tappet providing a clearance between said push rod seat and said one end of said push rod; said push rod having a lubricant entrance port in said end; said tappet having a lubricant passageway communicating with a gallery; said passageway having an outlet port in said push rod seat in a position oifset from said entrance port so as to be non coincidental thereto to prevent direct flow therebetween; and said outlet port being in limited communication with the side of the push rod to allow limited exhaust of some lubricant even when said rod end is forced against said seat as well as allowing flow to said entrance port when said rod end is lifted from said seat.

6. A mechanical valve lifting tappet comprising: a body having a push rod seat on one end, and an annular groove around said body adapted to register with an oil gallery in the tappet bore of an internal combustion engine; a lubricant flow passage in said tappet extending between said groove and said push rod seats; said tappet having a central axis; and said passageway emerging in said push rod seat in an off-center position with respect to 6 said central axis whereby said passageway is adapted to be off set from a lubricant entrance port on the central axis of a push rod.

References Cited in the file of this patent UNITED STATES PATENTS 2,718,219 Chayne et a1. Sept. 20, 1955 2,983,335 Etchells et a1. May 9, 1961 FOREIGN PATENTS 571,885 Great Britain Sept. 13, 1945 

1. IN A VALVE OPERATING MECHANISM OF AN INTERNAL COMBUSTION ENGINE, THE COMBINATION OF THE FOLLOWING COMPONENTS: A TAPPET ADAPTED TO RIDE ON A CAM SURFACE AND INCLUDING A PUSH ROD SEAT ON ONE END THEREOF; A HOLLOW PUSH ROD HAVING ONE END INTERFITTING WITH SAID PUSH ROD SEAT AND IN AT LEAST ONE POSITION OF SAID TAPPET PROVIDING A CLEARANCE BETWEEN SAID PUSH ROD SEAT AND SAID ONE END OF SAID PUSH ROD; SAID PUSH ROD HAVING A LUBRICANT ENTRANCE PORT IN SAID ONE END; SAID TAPPET HAVING A LUBRICANT PASSAGEWAY COMMUNICATING WITH A LUBRICANT GALLERY; EACH OF SAID TAPPET AND PUSH ROD COMPONENTS HAVING A CENTRAL AXIS, AND AT LEAST ONE OF SAID PUSH ROD PORT AND TAPPET PASSAGEWAY BEING OFF THE CENTRAL AXIS OF ITS RESPECTIVE COMPONENT, WITH SAID PASSAGEWAY COMMUNICATING WITH SAID PUSH ROD SEAT AT A POSITION OFFSET FROM SAID LUBRICANT ENTRANCE PORT WHEREBY LUBRICANT FLOWING FROM SAID PASSAGEWAY TO SAID PORT MUST FLOW THROUGH SAID CLEARANCE BETWEEN SAID PUSH ROD SEAT AND SAID PUSH ROD END TO THEREBY REGULATE THE FLOW TO SAID HOLLOW PUSH ROD. 